Doctor mechanism



w. F. HucK nocToR MECHANISM Cet. 7, 1958 2 Sheets-Sheet 2 Filed NOV. 15.. 1948 vmmwmwrwlf L United States Patent DOCTOR MECHANISM William F. Huck, Forest Hills, N. Y., assignor to R. Hoe Cip., Inc., New York, N. Y., a corporation of New Application November 15, 1943, Serial No. 60,075

6 Claims. (Cl. 1431-157) This invention relates to doctor mechanism for rotary intaglio printing machines.

It is an object of the invention to provide a-doctor mechanism in which the operating parts are thoroughly erliclosed and protected from ink, paper particles and the li e.

Another object of the invention is to provide a doctor mechanism of great rigidity, in which vibration is minimized.

Another object of the invention is to provide a doctor mechanism'in which very delicate adjustment of doctor blade pressure against the cylinder may be' obtained.

A still further object of the invention is to provide a doctor mechanism in which the pressure of the blade against the cylinder may be set accurately and the preset pressure may be re-established automatically upon swinging the doctor mechanism from non-operating to operating position.

With the foregoing and other objects in view, which will appear as the description proceeds, the invention resides in the combinations and arrangements of parts and in the details of construction hereinafter described and claimed.

In the drawing:

Figure 1 is an end elevation of the doctor mechanism with certain parts removed to show details `of internal construction;

Figure 2 is a plan view of the doctor mechanism of Figure l; and

Figure 3 is a front elevational view thereof.

The doctor mechanism is of the general type shown in Little Patent No. 2,049,846 and Heller Patent No. 2,097,- 791, and in which the doctor mechanism is carried on a reciprocating carriage, the doctor proper being supported by arms pivotally mounted on a shaft supported by the carriage, for swinging it into and out Iof operating position, and the pressure of the doctor blade against the cylinder being regulated by means of springs exerting a torque around the shaft on which the doctor is pivotally carried.

The general details of such a doctor mechanism and of the cooperating printing machine parts being well known, they will not -be described herein, the present description being conned to the novel features of the invention and such of the conventional elements as are necessary for an understanding thereof.

ing cylinder 1, carried on a shaft 2, which is supported in the machine frame on bearings (not shown) in the usual way. There is also indicated a cylinder housing 3, which may be of usual type. The doctor blade 4 bears against the cylinder as indicated and is preferably disposed at a high and nearly radial angle with respect to the cylinder.

Tracks 5, which are attached to the machine frames 6 (Figs. 2 and 3) support the sliding carriage 7, which is reciprocated -by a doctor reciprocating mechanism 8, being coupled thereto by means of a connecting rod or In Figure 1 there is indicated a rotary intaglio printtice pitman 9 and stub shaft and bearing assembly 10. Pedestals 12 are mounted on the carriage 7, and the doctor supporting shaft 13 is rotatably journaled in bearings 14 in the upper part of the pedestals. The doctor supporting arms 16 are pivotally carried on the shaft 13 by means of bearings 17 and in turn carry a doctor supporting bar 18, which is fastened to arms 16 by means of bolts 19. Bar 1S is slotted andreceives an angle 20 formed on a lower member 21 of a doctor clamp arrangement which includes also an upper clamp 22 fastened to the clamp 21 and thus holding the doctor blade proper 4. The precise construction of the doctor blade assembly is not material to the present invention and hence is not shown in detail. The angle 20 is firmly held in the slot in bar 18 as by means of screws 23. Bar 18 is preferably round as shown and received in arcuate seats 24 in the arms 16 to permit change of the angle of the -blade 4 where desired.

Each of the arms 16 is formed with a hollow housing or casing 25, which encloses the operating mechanism described below. In the space between the bearings 17 o'f each arm 16 there is mounted an arm 30 which is Xed to the shaft 13. Shaft 13 and the arms 30 xed thereto may be rotated by any convenient means, such as worm gear assembly 31 and crank 32, so as to move the doctor to and from operation position, and may be locked in any desired position. In operation, the arms 30 may therefore be considered as fixed in position.

A spring 35 is carried within a bore formed in each arm 38 and reacts against a cover plate 36 fastened to the casing arm 16, thus tending to lift the doctor blade otf the cylinder or to rotate the arm 16 clockwise. Pressure of the spring 35 may be regulated by means of a member 37 threadably carried in the arm 30 or in any other convenient way.

The upper part of each arm 30 has a threaded bore.

38 which receives a correspondingly threaded rod 39, which passes through an opening in the rear wall of the housing 25 and which may be turned by a hand wheel 40. Rod 39 adjusts the position of a member 41 that is secured to a rod 42 which is slidable within a socket 43 formed in the arm 16. A spring 44 is compressed between the member 41 and an abutment 43 formed in the housing 25 and surrounding socket 43. The spring 44 thus opposes the action of the spring 35, tending to force the doctor blade 4 down against the cylinder 0r to rotate the arm 16 counter-clockwise.

Springs 35 and 44, in addition to regulating the doctor pressure in operation, also couple the arms 30 to the arms 16 (within the hollow casings 25 in which they are enclosde), 'for swinging the arms 16 to and from operating position when the shaft 13 is rotated as hereinafter described in detail.

A gauge 45 is provided, being suitably connected to the member 41 by a rod 46 and protruding through the upper cover 47 of the housing 16 so as to be Visible from the exterior of the housing. Gauge 45 may be calibrated so as to read in pounds of pressure or in any other convenient natural or arbitrary units.

The bar 18 and arms 16 constitute a relatively massive assembly, this being desirable for obtaining the maximum rigidity of the parts, and the center of gravity of this assembly is very considerably offset from the center of the shaft 13, so that the weight of the parts, if unopposed, would tend to apply a relatively heavy pressure on the blade 4.' In the best practice, it is found that relatively light doctor pressures are preferable and, accordingly, the spring 35 is utilized to counterbalance the weight of the parts, and the spring 44 is adjusted to produce whatever doctor blade pressure is desired. y

In operation, the pressman will ordinarily not have to adjust the spring 35, which may be set for somewhat which is received yin a correspondingly threaded member 50 which operates Vthe gauge 4S.V The covers '47 being removed, thepressman mayadjustconnecting rods 46 so that gauges`45 will give a zero reading when the doctor mechanism is exactly balanced. The ,covers 4f] may new be put back in place and Vall further necessary adjustments may be made by turning the hand wheels 40. The gauges 45 vwilljread the vactual doctor pressure applied in whatever units ,maybe-desired, and will not require resetting unless 'there is a major change in the mechanism, such as the substitution of a doctor blade of dinerent width, or the like. Small changes in the dimensions of the parts such as may occur due to wear of the doctor blade will obviously not affect the balance condition materially nor will the doctor pressure be materially aiected. Theworm gear .31 may be suitably calibrated or provided with stops `to limit `its movement in either direction when bringing the doctor into operating position or swinging it -bac'ktrom operating position, the total arc of movement between thesetwo positions being approximately 90 or thereabouts.'` v, n

What is claimed is:

1. In a rotary intaglio doctor mechanism, the combination with a doctor, of a plurality of doctor supporting arms and pivotal supports therefon, the. arms being formd as hollow casings" and the center of gravity of the doctor, andthe 'said supporting armsbeing displaced from thepivotal-axis'` so 'thatthe force of gravity tends to press the doctor against a printing-cylinder, members enclosed within the casings for pivoting the arms to move the doctor toward and away from operating position, and spring means also enclosed within the casings and actinglbetweenv the same 4and theY enclosed members fory reducing the Vdoet` pressure due tol the weight ofi the parts -and for coupling the said arms to the said members for movement therewith."v

2. Mechanism according to claim l, in which the spring means comprisesaspring for counterbalancing the weight of the pivoted parts and comprises also an adjustable opposing spring for regulating the doctor pressure.

3. In a rotary intaglio doctor mechanism, the combination with the doctor, of a rockable shaft, a plurality of doctor supporting arms pivotally carried by the shaft,

the arms being formed as hollow casings and the center of gravity of the doctor and the said supporting arms being displaced from the pivotal axis so that the force 0f gravity tends to press the doctor against a printing cylinder, members fixed to the shaft and enclosed within the casings for pivoting the arms to bias the doctor toward and away from operating position, and spring means within the casings and acting'` between the same and the enclosed members for reducing the doctor pressure due to the weight of` the parts and for coupling the said arms to the said members for movement therewith.

4. Mechanism according to claim 3, in which the spring means comprises a spring for counterbalancing the weight of the pivoted parts and comprises also an adjustable opposing spring for regulating the doctor pressure.

5. 1n a rotary intaglio doctor mechanism, comprising a doctor and a pivotally mounted doctor supporting structure, in which the center ofgravity of the doctor and its supporting structure is displacedzfrorn thepivotalaxis so thatrthe force of, gravityL tends to press thevdoctor against a printing cylinder, andjinjcombinatiom,means for clounterhalancing the moment about the pivot axis due to the weight of the doctor and supporting structure and an adjustable spring means acting against the doctor supportingstructurefor.regulating the doctor pressure against the cylinder.

6. In alrotary intaglio doctor mechanism, comprising v a doctor and a pivotally mounted doctor supporting structure, in which the center of gravity of the doctor and its supporting structure is displaced from'thenpivotal axis vso thatthe force of gravity tendstopress the .doctor against a printing cylinder, anduin combinatiomspring v means for ounterbalancingthe:moment about theV pivotal A axis due to theweightfofthe parts and adjustable spring means opposing the counterbalancing spring means 'for .regulating the-pressure of the doc ton u j Y y ReferencesCited inthelileofthis patent UNITED STATES PATENTS Great Britain Jan. 27, 1931 

